heres my latest mad cap idea-single sub tank.

[Studboy]

Marcus, how did you close off the handlebar ends? Did you have them welded shut?

 

[Robin13]

The marzocchi forks were the magnums. I tought they were on alot of ktm/husky models till 98 or something, I'm not sure. But If you have the compression damping in one leg and rebound in the other and landing a jump for instance the forces will be uneaqually defided between the legs and the axle and clamps will have to keep everything straight and fight flex.
A diffferent springrate will cause different damping caracteristics. A stiffer spring will compress slower and rebound faster, so if you change the springrate by using subtanks you will also change the damping caracteristics of the fork.
I'm not sure ofcourse, but the extra forces the seperate damping on the marzocchis will cause more stress on the axle/clamps than the single subtank idea will.
Wel this is how I see it, if I'm wrong please say so.

 

[russ17]

The way I see it once the forks are bolted to the axle it acts as one. This is why they are able to run reb in one leg, and comp in the other. Different spring rate in one leg versus the other to create a different spring rate.

 

[marcusgunby]

The fork level is 100mm in the fork leg(it needs to be 110mm for me as im not bottoming)-ive heard i should go to half that with a sub tank, but if i start way low and get bottoming(which i should) i can turn in the adjuster to see if i can tune it out without harshness.if this isnt possible then i can add oil, i wanted to start low as then i know i have the full airchamber function to start with.At 2.5mm it sounds like im not too far from the enzo system.

i booked tomorrow off work to test the setup but no tracks are open-its really wet here:(

 

[mop]

Robin13:
For your information, SPRING rate does not affect DAMPING characteristics, since they are separate. Overall performance changes when either one is changed, but they do not affect each other. In other words, you cannot increase the compression damping force of the fork by going to a stiffer spring, it will just stiffen the spring force of the fork. Spring and damping are separate elements which make up the total performance of the fork (or any suspension component). The spring is load or position sensitive, and the damping is speed sensitive. The subtank system makes the spring character speed sensitive as well. When the fork is compressing slowly, it feels like a low oil level, and when it compresses quickly, it feels like a high oil level (as long as a high oil level is set in the fork. At what speed the high oil level feeling kicks in is determined by the restriction between the two volumes (the adjustment).
I know how this feels with BOTH forks set with subtanks, but I don't know how it will feel with only one side set up. My GUESS is that it will feel weird. That is what I was getting at.

 

[marcusgunby]

Marcus, how did you close off the handlebar ends? Did you have them welded shut?

sorry i forgot to answer this, i made alittle setup , but its not easy to copy, i used some rubber plugs then put a screw and nut through them, tightened the screw so it becomes a tight fitting, then to make sure i put super glue down the ends of the bars.

Mop i just dont see how it will feel weird-bottom maybe but forks can only react as a pair, with a broken spring it will feel weird due to it hanging down in the stroke, it wont do this as both fork springs are ok, i think its all in your head-you expect it to act weird so it must :yikes:

 

[mop]

Marcus:
My concern regarding the "weirdness" is mostly due to my lack of experience working with front forks which have dramatically different set ups in each leg. I've worked with different rate springs in each leg, usually no more than a rate or two different, and have experienced no ill effects. BUT, I wonder about the dramatic difference between your two legs because you've set them up with one leg having a HUGE combined air volume (100mm oil level in one fork leg, and 150cc of volume in the subtank (handlebar).The other leg, I assume you've run a lower oil level? The subtank volume is large enough for both legs, but it is only being accessible to one leg. MAYBE it will all come out the same as running two legs set up the same, I don't know!! That will be interesting! Let me know how it works!

 

[bclapham]

Marcus:..............I wonder about the dramatic difference between your legs

come on steve- this one is all yours!!! :yikes: :laugh:

i really hope it dries up in the UK soon and Marcus can go out and test this thing!!!

 

[steve125]

come on steve- this one is all yours!!! :yikes: :laugh:

i really hope it dries up in the UK soon and Marcus can go out and test this thing!!!

Bruce, Marcus is looking for another sub-tank location. You don't think he would wire in the little guy??? do you?? talk about a dramatic difference between the legs!!!! :yikes: :rotfl:

 

[marcusgunby]

Always hijacking my threads with inuendo:)

 

[bclapham]

in all seriousness, i dont think it will feel wierd- the fork legs are bolted together and act as one- yes, they can flex fore and afte, or maybe twist at full extension, but by the time the fork is using the airspring, its at the last 1/3 of travel and there wont be any leverage to do either.

with a bad spring, it would affect the top of the stroke and hense, more leverage for twisting type forces.

 

[jmics19067]

two things that come into question in my mind,

1st is the hole drilled into the bars, I would guess that there is some cycling of stress in between the bar clamps. when you are exerting downward pressure on the grips you will be trying to raise the center into a W type shape. With the hole being round and all forces evenly distributed(no stress risers) and the hole being in the bottom with the fitting being compressed( the center of the bar is going to try and flex upwards and make the hole smaller) . I don't see the handlebars tearing themselves apart but..........?

2nd... with only one fork leg being vented the other one will still have the "standard" air spring.even if it is only the rebound side of dampening fork leg you are still trying to squeeze a given amount of air into the same given space.Knowing nothing of these forks I am still figuring that they are sealed and the air doesn't vent somewhere's on the one leg......?

I like the innovation, it is an excellent idea,sharp on taking a proven idea and making a manageable improvement. extremely little extra weight and no extra space being taken up.Even if my two questions are warranted they could easily be answered with a solid top bar mount to help support any upward movement of the center and a TEE fitting to connect the forks.

 

[marcusgunby]

trust me if i break these bars due to that hole i wouldnt be on this board, i would be racing RC;) they are seriously strong bars and that hole in the centre will not be a issue-i wouldnt do it with std kx bars but they probably still wouldnt break IMO. A few people have done this type of mod with both fork legs on ktmtalk and no reported failures.

Not at all sure on the 2nd question -i think i have not read correctly what you mean? could you try to explain more the part you are thinking about?

 

[marcusgunby]

Hi mop-putting this on drn as i tried to e mail you back, but it gets returned straight away? can you e mail me another address to reply to?

 

[mop]

Marcus:
I don't know.......I'll try emailing you again. I have another address, but I can't access it through my computer, I have to go thru another person.

Mop...

 

[jmics19067]

trust me if i break these bars due to that hole i wouldnt be on this board, i would be racing RC;) they are seriously strong bars and that hole in the centre will not be a issue-i wouldnt do it with std kx bars but they probably still wouldnt break IMO. A few people have done this type of mod with both fork legs on ktmtalk and no reported failures.

Not at all sure on the 2nd question -i think i have not read correctly what you mean? could you try to explain more the part you are thinking about?

I am confused sorry I was under the impresion that you had a KTM with the different forks one rebound one compresion. ....
ok back to what I was trying to say If you run a subtank on one fork leg the other fork leg will have the standard air spring as it compresses right? will the air springs between the 2 different forks be an even average or will the "standard " fork's air spring rise exponentially greater than the one with the sub tank . With the possibility of the "standard fork" air spring being exponentially greater,negating most of the improvements from the "sub tank " fork.

Will two forks ,set up equally, sharing one sub tank feel the same compared to the averaging of two different set up forks one with sub tank one without is my question.

Is my thoughts clearer? I am not even sure if it is a valid question but like I said it could be easily cured with a Tee fitting.

 

[bclapham]

Guys- just wait for it to stop raining and let him go try it. I work in a chemistry research lab and so many times ive seen people talk themselves out of doing experiments since they could find several reasons why it might not work. You insist they do it, and hey presto, a lot fo the time things will work.

It goes the otherway to, things that should be dead certs, just dont work.

Bottom line, to establish if an idea will work or not, you have to test it.

 

[Danger]

Wait for it to stop raining? Yeah right. We could be waiting along time. Its always raining in England isn't it?
Just get out there Marcus. I've been out for three rides since this thread started. I'm begining to loose interest. I'm sure the Airbar is faultless sitting in your garage.
I was hoping to have my own to test today, but unfortuanatly couldn't get any parts here.

 

[jmics19067]

Guys- just wait for it to stop raining and let him go try it. I work in a chemistry research lab and so many times ive seen people talk themselves out of doing experiments since they could find several reasons why it might not work. You insist they do it, and hey presto, a lot fo the time things will work.

It goes the otherway to, things that should be dead certs, just dont work.

Bottom line, to establish if an idea will work or not, you have to test it.

well I for one didn't mean to be a party pooper Bruce. The two questions I asked did have the fine print of not even knowing if the questions were even warranted. I don't want Marcus to give up just because I thought of 2 maybe issues.Heck I would be surprised if he scrapped the project because I said something. What was his old sig line "listen to what people say but don't listen to them"

I liked the idea, I figured since it is up on the board the idea was up for discussion, I can't think of anything wrong with the idea ,but I thought of 2 concerns I would have and offered the direction I would take IF the concerns had to be dealt with....That and a dollar might get you a cup of coffee as the old saying goes

Sorry Marcus If I overstepped my boundaries , I do like the idea

 

[marcusgunby]

LOL dont anyone say its not open for discussion-i think bruce was just saying theorys are only good in cyberspace and we need testing to prove it, i just did a 18 hour stint helping a friend at the NEC sx race , i will try hard to get out midweek.I know people are eager to know the results but it only takes a few hours to make your own;)

 

[jmics19067]

LOL dont anyone say its not open for discussion-i think bruce was just saying theorys are only good in cyberspace and we need testing to prove it, QUOTE]

so untrue theories are good in the pub :nener: especially after you get done testing

 

[marcusgunby]

well it wasnt good news:( i got to a good track for testing, it was a jumpy track with some real good rough sections, the sub tanks didnt do much at all, even from full hard to soft it felt like just 2 clicks on the comp adjuster-i think my setup with the 2.5mm tubing(or the control valve) is too restrictive, trouble is to get more than 2.5mm i have to drill out the fork caps and i really didnt want to do that-so suggestions are???

 

[mop]

Marcus:
I would think that if you have NOT drilled out the fork cap bleed hole (5mm?) to install a hose fitting, then the hole in your fitting or hose end must be quite small, possibly smaller than the i.d. of the hose? Ideally, the hose i.d., fitting i.d., etc, should be larger than the restriction in the adjustment, so that the adjustment restriction is the point of greatest restriction....
Drilling out your caps is not that big a deal, if you decide to remove the system, Enzo sells "plug" screws to fit the modified hole. The modified hole and thread for the Enzo fitting is 8 x 1.0mm.

 

[marcusgunby]

thanks mop i will have a think bout it:)

 

[Chili]

When removing the the TooTech System on LazyBoy's 03 that had the caps drilled out our suspension guy just replaced the fitting with a schraeder valve.